Anuria or anuresis occurs when the kidneys aren't producing urine. A person may first experience oliguria, or low output of urine, and then progress to anuria. Urination is important in removing both waste and excess fluids from your body.

What level of urine output is considered anuria?

Anuria: It is characterized by reduced urine output (<100mL urine per day), reflecting renal injury. Oliguria: It is defined as reduced urine output below 400mL/day. Such urinary volume is insufficient to excrete the daily osmolar load.

What is considered oliguria?

Oliguria is defined as urinary output less than 400 ml per day or less than 20 ml per hour and is one of the earliest signs of impaired renal function.[1] It had been described early in the literature when Hippocrates identified the prognostic importance of the urinary output.